Method of coating metal foils with a polymerizable resinous coating



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METHOD OF COATING METAL FOILS WITH A POLYMERIZABLE RESINOUS COATING Filed Feb. 16, 1959 1'1" Sheets-Sheet 1e COMPRESSOR EDWAR E. AS HER IN VENTOR.

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3,215,558 METHOD OF COATING METAL FOILS WITH A POLYMERIZABLE RESINOUS COATING I Edward E. Dascher, 402 Garden Blvd., Garden City, N .Y.

Filed Feb. 16, 1959, Ser. No. 793,612 2 Claims. (Cl, 117-430) This application is an improvement; over and a continuation-in-part of applicants pending application for patent on Electrically. Conducting Adhesives and Foil Conductors filed on November 12, 1954, under Serial No.

for bonding and/or for additional coatings and penetrants; =(3) vapor deposition of metals on foil in vacmini; (4) and anodic oxidation of metals to serve as dielectrics.

Specifically, applicant simultaneously by a continuous and progressive process: (1) synthesizes, in successive stages of and by polymerization processes, a dielectric coating on one side of the metal foil, such synthesized coating including a formed modification of a polymer or copolymer, or a formed resinous polymer, or copolymer; (2) pressure molds the synthetic resultant uniformly, densely and by successive, and fused deposition on the foil for dielectric gauge controlled development; and (3) anneals the metal foil component.

United States Pat "t Thus, the invention lends itself to economic and highspeed production, gives the conductor longer life, more 'e'fiicient performance and wider utilization.

Broadly, the invention provides an insulated electrical conductor for use in electric or electronic circuitry and in components of such circuitry, the said conductor having an electrically conducting metallic foil .of selective gauge and a reinforing dielectric plastic coating of selective gauge thermionically' or molecularly bonded to the virgin foil metal and also mechanically bonded to the oxide thereof.

Oneof the objects of the invention is to effectuate and.

provide such a foil and coating with dimensional, textural and property uniformity and stability; with higher temperature operational characteristics involving less or no coolants; with no cold roll, creep or delamination characteristics in operation or during winding and stacking formation thereof; and with foil and coating characteristics-of compatible and cooperative electrical, physical, chemical and thermal advantage.

Another object of the invention is to provide a conductorof the above nature and of selectable dimensions and'values and embodying such electrical, thermal, physicaliand chemical characteristics as to allow economic, simplified and efficient fabrication therefrom of component parts or elements in electronic circuitry at the manufacturing or industrial site. Thus, the conductor is capable of delivery to the industrial site in continuous lengths pursuant to value specifications as in roll form and the fabricator engages in the required winding, stacking or other -formable operation for the production of a component unit or other element in electronic circuitry.

' Thereafter, "the formed unit is bonded by the fabricator by. a simple reactivation operation of the dielectric for unit completion.

Another object of the invention is toprovide a conductor of the above nature capable of use in miniature, sub-miniature and conventional electronic circuitry; capable of use as a fillable capillary and inflatable-conducting tube for use in gauges, fuses, testing devices or other purposes as will appear; capable of reducing weight and space of components or elements formed of such conductor, and of uniformly and efliciently dissipating uniform heat development in each convolution or layer or lamination of the windings and stackings from such conductor to permit efiicient and high voltage per-mil of dielectric operation for longer hours, at higher temperatures, at substantially uniform performance and without or diminution of use of coolants. I

Metallic foil heat developed in operation of the condoctor of the invention as a Wound or stacked compo nent by reason of dielectric reflective, refractive and dispersive values is efiiciently absorbed by the dielectric component for each convolution or lamination and is dissipated by continuous and immediate lateral emission and conduction to the component edges which area:- posed for ambient temperature absorption. Such .phenomena are attributable to the contacts between the-dielectric, the oxide and the virgin foil, which involve molecular and mechanical integration and also to the-homogeneous, dense and uniform gauge characteristics of the dielectric. There is further a complete absence'of permeability, pockets and foreign material-containing areas between said contacts to eliminate resulting adverse effects.

A further object of the, invention resides in the provision of a conductor having anannealed or'orientedmetallic foil component and a simultaneously oriented and pressure-compacted and uniform dielectric coating component at least on one side of the foil. Theconductor, moreover, partakes of the physical and improved strength of the coating. Thus, conductors derived from metallic foil from about .005 down to about .000175, inch in gauge and dry coatings from .00025 down to .0000; inch in gauge have been formed, capable ofutilization for fabrication. Of course, the conductor may have the uncoated side provided with a dielectric by subsequent-pperations and by any method.

Another feature of the invention resides in the improvement of the metallic foil component of the invented conductor as it comes from the rolling mill resulting. from thermionic, pressure and annealing conditions. g Y

Anotherfeature of the invention resides inmethod, apparatus and product for forming either the conductor of the invention or any other type of conductor having a one sided dielectric coating into folded longitudinal edge form to control width and improve characteristics for component formation in circuitry.

Another feature of the invention resides in method, apparatus and product for forming the conductor ofthe invention or any other foil conductor having a dielectric on one side into capillary, fillable, inflatable and flexible tubular form to improve characteristics for compo nent formation in circuitry and to serve other electrical functions.

These objects and other incidental ends and advantages of the invention will hereinafter appear in the progress of the disclosure and as pointed out in the appended claims. I j]:

Accompanying this specification are drawings showing various illustrative embodiments of the invention wherein: FIGURE 1 is a view in perspective of the remote control panel for effecting operable conditions inthe 'various and continuous sections of the reaction chamber or tower plant; :1

FIGURE 2 is a schematic view in perspective illustrating a preferred production assembly linefor manufacture of a form of the conductor of the invention 'wher'ein 'is shown a coatingplant; the tower plant wherein heating, annealing, evaporation, combustion, synthetic product deposition under controlled temperature and pressure conditions, orientation and cooling take place; a slitting plant; an editing plant for imperfections; a folding plant for effecting one form of the invention; and an ultrasonic welding plant for the opposing edges of the folds;

FIGURE 3 is an enlarged sectional view diagrammatically showing molecular and physical bondage between the dielectric, the oxide and the virgin metal of the invented conductor and other characteristics;

FIGURE 4 shows an enlarged transverse sectional view of afiipped-over or folded edge formation of the invented conductor shown in FIGURE 3;

FIGURE 4a is a schematic overlap form of the conductor;

FIGURE 5 shows the conductor of FIGURE 4 in plural ply formation;

FIGURE 6 is an enlarged sectional view of a tubular form of the invented conductor;

FIGURE 7 shows the conductor of FIGURE 6 in plural ply formation;

FIGURE 8 is a view in elevation showing the conductor of FIGURE 6 in cylindrical form;

FIGURE 9 is a diagrammatic view taken transversely of results of a folding operation of one ply of metal foil with or without dielectric coating;

FIGURE 10 is a view similar to FIGURE 9 but with two plies of metal foil resulting from a folding operation with or without dielectric coating or other insulation;

FIGURE 11 is a similar view but with a plurality of plies of foil, plastic or other dielectric resulting from a folding operation;

FIGURE 12 is a fragmentary and diagrammatic view in perspective showing the metal foil as it comes from the rolling mill containing an oxide and protective mineral oil film plus a coating application for final synthesis of the dielectric coating;

FIGURE 13 is a fragmentary and diagrammatic view in persepective showing the specimen of FIGURE 12 after complete subjection to the vertical tower operation;

FIGURE 14 is a sectional view partly fragmentary showing a form of the coating plant, the entry feeds thereto the inlet feeds to the tower plant;

FIGURE 15 is a view in perspective partly broken away showing other details of the coating plant not shown in FIGURE 14;

FIGURE 16 is a view in perspective partly broken away showing details of structure for control of amount of coating application;

FIGURE 17 is a view in perspective of the plural tiers of the vertical tower plant and the external processing rollers and rewind of the processed foil conductor;

FIGURE 17a is a schematic view of FIGURE 17 exemplifying vertical operation and operation;

FIGURE 18 is a fragmentary view in perspective of a detailed structure of a multiple flue associated with the tower plant for control of entry of selected values of cubic feet of air per minute thereto;

FIGURE 19 is a view in perspective showing preliminary arrangement prior to folding for aligning a plurality of laminations as seen in FIGURES 10 and 11;

FIGURE 20 is a diagrammatic view showing details of temperature and volumetrically controlled air supply to sections of the tower plant;

FIGURE 21 is a detailed view in perspective showing the top tier of the tower plant, structure for air introduction, heaters, and temperature reading instrumentation;

FIGURE 22 is a view in perspective of a bowed type of roller and the mounting therefor;

FIGURE 23 is a sectional view of FIGURE 22 across the plane 2222 thereof;

17b horizontal FIGURE 24 is a sectional view of FIGURE 23 across the plane 24-24 thereof;

FIGURE 25 is a fragmentary perspective view partly broken away showing port and other details at the upper tower tier for discharge of products of combustion and other active fumes to a catalytic combustion chamber;

FIGURE 26 is a fragmentary perspective view at the top of the upper tower tier showing details of a top drum, controls therefor and dewrinkling rollers for the processed conductor;

FIGURE 27 is a diagrammatic and perspective view showing an air controlled dancing roller for the coated metal foil stock preliminary to feed into the tower plant;

FIGURE 28 is a view in perspective of a slitting plant for the completed and processed conductor;

FIGURE 29 is a view in perspective and partly diagrammatic showing editing or means for reading dielectric strength of coating on web after the slitting operation;

FIGURE 30 is a sectional view of FIGURE 29 across the plane 30-30 thereof;

FIGURE 31 is a view in perspective of apparatus for direct wind of the processed conductor adjacent the top of-the tower plant.

Basic considerations of inventi0n-FIGURES 17a-17b For a broad comprehension of the invention before proceeding with a detailed description of apparatus, method and end product, brief reference is made at this portion of the specification to the treatment and mounting of the metallic foil stock coming from the rolling mill with the conventional oxide and mineral oil surface and to the manner and type of in situ synthetic formation and deposition of dielectric resin from the basic materials in the coating-all resulting in the fundamental structure shown in FIGURE 3.

The metallic foil stock whether aluminum or other non-magnetic and electrically conducting material including copper, is first subjected to a controlled thickness of coating on either side and then to movement under controlled velocity and controlled conditions of stretch or tension'through a heating or reaction chamber 106' (see FIG. 17a) comprised of a plurality of communicating I tiers 106a, 1061: and ltic each having independent temperature as well as volumetric air-inlet systems, the latter being indicated by 109, and 111 respectively. At the bottom of lowermost tier 106a are independently adjustable dampers 211 and 212 to control size of inlet 106a for air inlet control and to admit coated foil or web 101a, while at the top of tier 106c and at roof portion 176 are independently adjustable dampers 185 to control exhaust of reaction gases and suspensions through the pair of exhaust conduits 186. The exhaust conduits communicate with an exhaust duct 113 having exhaust fan 112 and there are independently adjustable dampers 189 therebetween. On the top of roof 176 there is a closeable opening controlled by independently adjustable dampers 184 to form another adjustable air inlet 1060 for air downdraft for cooling and annealing purposes. Web 101a also emerges from inlet 106C.

The air inlet systems 109, 110 and 111 for the respective tiers have direct entry (arrow indicated) on the un coated side of the web through nipples 309a, 3091 and 3090 while on the coated side of the web, entry is effected by branches 310a, 1510b and 3100 coming off chambers 308a, 3081; and 3080.

The web 101a is under tension between lower roller 107 and top high and controlled constant torque drum 108 and is subjected in each of the tiers on both sides to various heats as afforded by resistance rods 115 or other heat producingmeans.

For making a dry coating of polyurethane of .00025 inch on aluminum foil of .0005 inch and of 12 /2 inches width from specified-bath materials at a viscosity value of Zahn cup #4, twelve seconds, and wherein the tiers aresix feet high, eight by eighteen inches on the sides, with a metallic foil unwind speed of forty feet per minute, temperatures, air-intakes, exhaust and pressures must have specific values.

Thus, by again referring to FIGURE 17a, the updraft .of air through bottom air inlet 106a is about 150 c.f.m.,

the air entry for tier 106a is about 150 c.f.m., for tier Gb air entry is about 250 c.f.m. and for tier 106e, air

entry is about 350 c.f.m. The downdraft through top air inlet 106c' is about 375 c.f.m., while the exhaust through duct 113 is about 350 c.f.m. Temperature in the tier 1060 is about 500 F., in tier 1061) about 750 F. and in tier 106a about 800900 F.

Pneumaticpressure on the uncoated side of web 101a is maintained at a higher value than on the coated side because of pressure conditions involved in the polymerization process and the depositions. This pressure differential may be accomplished in any suitable manner, but as seen in FIGURE 17a by branched feeds 310a, 1310b and 3100 to the'tier sides facing the Web coated side, by directional baflles 316s (seen in FIG. 18), and by differential manipulation of each of dampers 211-212, pair of dampers 185, pair of dampers 184, and pair of dampers 189.

The coating material of the bath in the example used and hereafter specified is adapted for in situ synthesis and successive and fused blow-molded depositions of high-polymeric macromolecular condensation and other compounds, and includes solids, liquids and active solvents therefor of different boiling points. Thus, in timed foil travel in chamber 106, the mill applied mineral oil 103 is substantially removed by fractional vaporization and the low boiling vaporized solvent is in a condition of polymerizable activity with the foil residue of the resin-forming materials. Then higher boiling solvents are vaporized to a condition of polymerizable activity and the foil residue itself is at least partly thrown into vapor pressure and suspended activity. All components and reactants are forced into close contact with web 101a by the air systems 109, 110 and 111 resulting in density of dispersion thereat and economy in minimizing loss through the exhausts.

Conditions in reaction chamber 1% caused by updraft through air inlet 106a', downdraft through air inlet 106a, air entry to the tiers through systems 109, 110 and 111, exhaust through duct 113, mobile vapor pressure equilibrium conditions of the bath ingredients and various temperatures, combustions near the rods 115 (highest temperature about 1500 F.) and pressures developed (Boyles law) all contribute to not only resinification, modification or resin formation in situ but also to blow-molded successive and fused deposition of layers of high density, polymerized particle aggregates from the chamber contents. The pneumatic pressures and directions thereof Within the chamber prevent the foil coating from free run-down and further serve as a brush type of molding for uniform distribution. The pressure of the reaction chamber 106 on the uncoated side necessarily exceeds that on the opposite side to serve as cushioning for the delicate foil gauges against the pressure effects from the coated side. If this type of posturing were not so, the foil, owing to its perforated and striated'nature as it comes from the mill, would become perforated and adhesively wrinkled with resultant shear, strain and tearing.

I Inthe reaction chamber 106, the metal foil component is elongated at about 450 C. whereby the stock variations' in gauge is reduced, the texture is made uniform,

free of gaseous, solid and fluid impurities and spatial imperfections, and is also annealed. Moreover and as seen in FIGURE 3, the conditions described and as indicated cause a thermionic type of bondage of the underlying resinous layers 138 to the virgin metal 137 (latter being excited to electronic emission) and through the interstices of the oxide of the foil as at 141 while also being mechanically and pressure bonded to the oxide as at 140 die posed over the virgin metal.

Fused redepositions under blow pressure effect uniformity and density of dielectric gauge and elimination of pockets, trappings and lamination facings, the latter being existent in other methods of plural coatings by redips or the like.

Moreover, the formed dielectric coating is subject to simultaneous annealing or orientation with the metal foil component by slow cooling at the upper part of the tower owing to the downwraft through inlet 106c. As a result, the dielectric texture has improved thermal and dielectric characteristics and transfers to the captive annealed foil its own higher values of tensile strength, impact resistance, and resistance to shear and pressure. Furthermore, the thermionic, or molecular type of bonding described, eliminates cold roll or creep due to varying conditions as etching and high temperature effects and eliminates deformation in stacking due to developed inside pressures.

Electrolytic factors exist in reaction chamber 106. Water from the condensation reactions is present in vapor form and other ionized groups are present. oxidation of the metallic foil, the pH value should be on alkaline side such as pH 8 at the exhaust area. The condoctor on emerging from the chamber is at about pH '7, while the pH of the coating bath is pH 9-pH 11.

By reason of the aforementioned processing and treatment, there results a conductor (see FIG. 3) of which. the annealed captive foil component 137 has better and more uniform electrical, thermal, flexible, forming, shape-conforming, foldable, windable and stackable characteristics than the foil stock 100 itself; the oriented dielectric component 138 is dense, uniform in gauge and texture, is not subject to cold roll or creep in production techniques required by reason of molecular and physical anchorage to the annealed metal component and has folding, creas ing, winding, stacking and shape-conforming characteristics.

The conductor comprised of the foil and dielectric coat ing as described when in tightly wound or stacked formation for resistance, capacity or other electrical function is capable of being bonded by the fabricatorlthermaliy as by induction after stacking or winding, or by the use of a solvent during stacking to integrate the unit. .Even when the dielectric coating is of thermoset resin, never? theless, it is controlled in the chamber for an intermediate stage of polymerization and is thermoplastic, but induction heating by the fabricator completes polymerization to infusibility.

The conductor after slitting operation as seen in FIG- URE 28 and to be described is capable of use in strip form and also in longitudinally-edged folded condition as indicated by numerals 127 and 127a in FIGURES 4 and 4a respectively. Such folding when the conductor is used for winding or stacking purposes eliminatesthe necessity of etching for uniform width, increases tensile strength and reduces possibility of shorts ofthe convolutions or plies as seen in FIGURES 5 and 7. Moreover, when the opposing edges are integrated such'as at the butt 142 by ultrasonic welding as indicated b31142" in FIGURE 6 and shown in resultant forms 144 and 129 in FIGURES 7 and 8 respectively, the conductor may be wound or used independently as a capillary. Such capillary is fillable and inflatable for electronic circuitry function either as a conductor, gauge, trip, fuse, capillarytube systems as in refrigeration, etc.

Bath ingredients is done continuously by doctor roller 104 on eithen side To prevent 

1. IN A METHOD OF COATING METAL FOILS, THE STEPS COMPRISING APPLYING A POLYMERIZABLE RESINOUS COATING TO FORM A RESIN TO ONE SIDE OF A TRAVELLING WEB OF METALLIC FOIL OF A GAUGE BETWEEN .005 TO .000175 INCH TO FORM A FLEXIBLE ELECTRICAL CONDUCTOR AND A DIELECTRIC NON-STRIPPABLY BONDED THERETO, HEATING SAID WEB AND COATING THEREON DURING COURSE OF TRAVEL BETWEEN 500*F. AND 900*F. BY AIR CONVECTION AND RADIATION FOR SOFTENING THE WEB AND FOR CURING THE COATING THEREON, SIMULTANEOUSLY AND CONTROLLABLY STRETCHING THE WEB AND COATING THEREON AND SIMULTANEOUSLY APPLYING HEATED AIR STREAMS TO EFFECT GASEOUS PRESSURES AT OPPOSITE FACES OF THE WEB WITH GREATER PRESSURE ON THE UNCOATED SIDE FOR CUSHIONING AND MAINTAINING THE WEB AGAINST FOLDING, WRINKLING AND DISPLACEMENT THEREOF AND FOR PNEUMATIC PRESSURE WIPING TO INSURE UNIFORM COATING, TAKING UP THE SLACK OF THE WEB WITH COATING THEREON FROM SAID STRETCHING, AND ANNEALING AND ORIENTING SIMULTANEOUSLY BY AMBIENT AIR FLOW AND SAID STRETCHING THE WEB AND THE COATING TO FORM A CONDUCTOR HAVING AN ANNEALED METALLIC FOIL COMPONENT AND A DIELECTRIC RESIN COATING COMPONENT BONDED THERETO AND OF UNIFORM THICKNESSES AND DENSITIES, SAID METALLIC FOIL BEING OF NON-MAGNETIC AND ELECTRICALLY CONDUCTING MATERIAL AND CONSISTING OF AT LEAST ONE METAL SELECTED FROM THE GROUP CONSISTING OF COPPER AND ALUMINUM. 